The present disclosure relates to a toner replenishing device for replenishing toner from a first container to a second container, and an image forming apparatus incorporated with the same.
An electrophotography image forming apparatus such as a printer or a copier includes a photosensitive drum for carrying an electrostatic latent image, a developing device for developing the electrostatic latent image into a toner image by supplying toner to the photosensitive drum, and a toner container for replenishing the developing device with toner. In an image forming apparatus for forming a full-color image, there may be employed a layout that an intermediate transfer unit is interposed between a toner container and a developing device. In such an arrangement, since the toner container and the developing device are disposed away from each other, a toner conveying portion for conveying toner from a toner discharge port of the toner container to a toner inlet of the developing device is formed.
In the above arrangement, if the toner discharge port can be formed at a position immediately above the toner inlet, it is possible to construct the toner conveying portion by merely forming a vertical conveying portion along which toner is allowed to drop downwardly. However, it is difficult to form a toner discharge port at a position immediately above a toner inlet due to the layout constraint of various units. In such a case, it is required to construct the toner conveying portion by forming a horizontal conveying portion for horizontally conveying toner, in addition to the vertical conveying portion. A conveying screw for conveying toner in the horizontal conveying portion is disposed in the horizontal conveying portion.
A toner conveying portion configured in such a manner that a horizontal conveying portion is disposed at a position posterior to a vertical conveying portion has a drawback that toner may be coagulated in the vicinity of an end portion of the vertical conveying portion (a start portion of the horizontal conveying portion), and smooth replenishment of toner may be obstructed. This is because the toner in the vicinity of the exit of the vertical conveying portion is likely to be conveyed backwardly by a rotational driving force of the conveying screw, and the toner is coagulated and clogs a convey path. Conventionally, there has been proposed a device constructed in such a manner that a torsion coil spring that is configured to swing as the conveying screw is rotated is mounted on the conveying screw for eliminating the above drawback.
With use of the conventional device, it is possible to prevent coagulation of toner in a region where the torsion coil spring swings. However, if toner is coagulated in a region outside of the region where the torsion coil spring swings, it is impossible or difficult to return the coagulated toner to a loosened state. Since it is difficult to manufacture a torsion coil spring having a sufficiently long length, there has been a demand for a technique of securely loosening the toner in a vertical conveying portion.
In view of the above, an object of the present disclosure is to provide an arrangement capable of securely conveying toner in a toner conveying portion configured in such a manner that a horizontal conveying portion is disposed at a position posterior to a vertical conveying portion, without coagulation.